Lock



FIG. 1 is a front left perspective view of a lock showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a plan view thereof;

FIG. 4 is a right side elevational view thereof of which the left side elevational view is a mirror image thereof;

FIG. 5 is a rear elevational view thereof; and,

FIG. 6 is a bottom view thereof. 

The ornamental design for a lock, as shown and described. 